jQuery
        .extend({

            createUploadIframe : function(id, uri) {

                    //create frame
            var frameId = 'jUploadFrame' + id;
            var iframeHtml = '<iframe id="' + frameId + '" name="' + frameId + '" style="position:absolute; top:-9999px; left:-9999px"';
            if(window.ActiveXObject)
            {
                if(typeof uri== 'boolean'){
                    iframeHtml += ' src="' + 'javascript:false' + '"';

                }
                else if(typeof uri== 'string'){
                    iframeHtml += ' src="' + uri + '"';

                }    
            }
            iframeHtml += ' />';
            jQuery(iframeHtml).appendTo(document.body);


            return jQuery('#' + frameId).get(0);    
            },
            createUploadForm : function(id, fileElementId, prams) {
                //create form    
                var formId = 'jUploadForm' + id;
                var fileId = 'jUploadFile' + id;
                var form = $('<form  action="" method="POST" name="' + formId
                        + '" id="' + formId
                        + '" enctype="multipart/form-data"></form>');
                var oldElement = $('#' + fileElementId);
                var newElement = $(oldElement).clone();
                $(oldElement).attr('id', fileId);
                $(oldElement).before(newElement);
                $(oldElement).appendTo(form);

                //增加文本参数的支持  
                if (prams) {
                    for ( var i in prams) {
                        var inputStr = '<input type="hidden" name="' + i
                                + '" value="' + prams[i] + '" />';
                        $(inputStr).appendTo(form);
                    }
                }

                //set attributes
                $(form).css('position', 'absolute');
                $(form).css('top', '-1200px');
                $(form).css('left', '-1200px');
                $(form).appendTo('body');
                return form;
            },

            ajaxFileUpload : function(s) {
                // TODO introduce global settings, allowing the client to modify them for all requests, not only timeout        
                s = jQuery.extend({}, jQuery.ajaxSettings, s);
                var id = new Date().getTime();
                var form = jQuery
                        .createUploadForm(id, s.fileElementId, s.prams);
                var io = jQuery.createUploadIframe(id, s.secureuri);
                var frameId = 'jUploadFrame' + id;
                var formId = 'jUploadForm' + id;
                // Watch for a new set of requests
                if (s.global && !jQuery.active++) {
                    jQuery.event.trigger("ajaxStart");
                }
                var requestDone = false;
                // Create the request object
                var xml = {}
                if (s.global)
                    jQuery.event.trigger("ajaxSend", [ xml, s ]);
                // Wait for a response to come back
                var uploadCallback = function(isTimeout) {
                    var io = document.getElementById(frameId);
                    try {
                        if (io.contentWindow) {
                            xml.responseText = io.contentWindow.document.body ? io.contentWindow.document.body.innerHTML
                                    : null;
                            xml.responseXML = io.contentWindow.document.XMLDocument ? io.contentWindow.document.XMLDocument
                                    : io.contentWindow.document;

                        } else if (io.contentDocument) {
                            xml.responseText = io.contentDocument.document.body ? io.contentDocument.document.body.innerHTML
                                    : null;
                            xml.responseXML = io.contentDocument.document.XMLDocument ? io.contentDocument.document.XMLDocument
                                    : io.contentDocument.document;
                        }
                    } catch (e) {
                        alert(e);
                        handleError(s, xml, null, e);
                    }
                    if (xml || isTimeout == "timeout") {
                        requestDone = true;
                        var status;
                        try {
                            status = isTimeout != "timeout" ? "success"
                                    : "error";
                            // Make sure that the request was successful or notmodified
                            if (status != "error") {
                                // process the data (runs the xml through httpData regardless of callback)
                                var data = jQuery.uploadHttpData(xml,
                                        s.dataType);
                                // If a local callback was specified, fire it and pass it the data
                                if (s.success)
                                    s.success(data, status);

                                // Fire the global callback
                                if (s.global)
                                    jQuery.event.trigger("ajaxSuccess", [ xml,
                                            s ]);
                            } else
                                handleError(s, xml, status);
                        } catch (e) {
                            status = "error";
                            alert(e);
                            handleError(s, xml, status, e);
                        }

                        // The request was completed
                        if (s.global)
                            jQuery.event.trigger("ajaxComplete", [ xml, s ]);

                        // Handle the global AJAX counter
                        if (s.global && !--jQuery.active)
                            jQuery.event.trigger("ajaxStop");

                        // Process result
                        if (s.complete)
                            s.complete(xml, status);

                        jQuery(io).unbind()

                        setTimeout(function() {
                            try {
                                $(io).remove();
                                $(form).remove();

                            } catch (e) {
                                handleError(s, xml, null, e);
                            }

                        }, 100)

                        xml = null

                    }
                }
                // Timeout checker
                if (s.timeout > 0) {
                    setTimeout(function() {
                        // Check to see if the request is still happening
                        if (!requestDone)
                            uploadCallback("timeout");
                    }, s.timeout);
                }
                try {
                    // var io = $('#' + frameId);
                    var form = $('#' + formId);
                    $(form).attr('action', s.url);
                    $(form).attr('method', 'POST');
                    $(form).attr('target', frameId);
                    if (form.encoding) {
                        form.encoding = 'multipart/form-data';
                    } else {
                        form.enctype = 'multipart/form-data';
                    }
                    $(form).submit();
                    //$(form).submit();
                } catch (error) {
                    handleError(s, xml, null, e);
                }
                
                if (window.attachEvent) {
                    document.getElementById(frameId).attachEvent('onload',
                            uploadCallback);
                } else {
                    document.getElementById(frameId).addEventListener('load',
                            uploadCallback, false);
                }
                return {
                    abort : function() {
                    }
                };

            },
            handleError : function(s, xhr, status, e) {

                // If a local callback was specified, fire it        
                if (s.error) {
                    s.error.call(s.context || s, xhr, status, e);
                } // Fire the global callback        
                if (s.global) {
                    (s.context ? jQuery(s.context) : jQuery.event).trigger(
                            "ajaxError", [ xhr, s, e ]);
                }
            },
            uploadHttpData : function(r, type) {
                var data = !type;
                data = type == "xml" || data ? r.responseXML : r.responseText;
                // If the type is "script", eval it in global context
                if (type == "script")
                    jQuery.globalEval(data);
                // Get the JavaScript object, if JSON is used.
                if (type == "json") {
//                    alert("111111===" + data);
                    eval("data = \" "+data+" \" ");
                }
                // evaluate scripts within html
                if (type == "html")
                    jQuery("<div>").html(data).evalScripts();
                //alert($('param', data).each(function(){alert($(this).attr('value'));}));
                return data;
            }
        })
